Radio frequency identification (“RFID”) tags are well known in the art. RFID tags typically include an RFID chip and an antenna secured to the RFID chip. The RFID chip can be encoded with information and other data, which can be retrieved as necessary through interrogation by an RFID reader. To interrogate an RFID tag, typically an RFID reader directed an electrical signal toward an RFID tag. The antenna of the RFID tag receives the electrical signal and propagates the electrical signal to the RFID chip. The electrical signal continues through the RFID chip, acquiring the information or data encoded on the RFID chip, and continues again through the antenna and returns to the RFID reader. The RFID reader can then interpret the information returned from the RFID chip and use such information as needed. It will be appreciated that the more efficiently the RFID tag manages the electrical signal sent by the RFID reader, the greater the effective range of the RFID tag.
RFID tags are used in a variety of industries including transportation, retail, inventory control, manufacturing and the like. An RFID tag can be attached to articles or items and can include information encoded on the RFID tag about those articles or items. RFID readers can interrogate the RFID tags and learn important or even critical information about the article or item.
A typical RFID tag 10 is illustrated in FIG. 1. The RFID tag 10 includes an RFID chip 20 mounted between two extended members 30, 40. In the prior art embodiment of FIG. 1, the two extended members 30, 40 are made of metal wire and form an antenna. Metal wire is a suitable material for an antenna for an RFID tag because metal wire is typically strong, flexible and a good conductor of radio frequency energy.
As illustrated in FIG. 1, when the RFID chip 20 is mounted between two sections of wire 30, 40 it forms a dipole. However, the known impedance of such a dipole results in suboptimal power transfer between the wire segments 30, 40 and the RFID chip 20. Such suboptimal power transfer can be caused by a loss of power due to reflection of power at the intersection of the RFID chip 20 and the wire segments 30, 40. Such a condition is commonly referred to as a mismatch between the RFID chip and the antenna. It will be understood that the loss of power will reduce the operating range of an RFID tag, and thus, negatively affect the performance of the RFID tag.
There is a need for improved performance for RFID tags. Specifically, there is a need for improved RFID tags to reduce or eliminate mismatch issues between RFID chips and accompanying antennas.